Cathode ray tubes to facilitate recording

ABSTRACT

A cathode ray tube with a conventional screen for providing a visible monitoring image is additionally formed with a second output portion on its envelope, the second output portion including a multiplicity of fibre-optics, electrically conductive particles, or other elements for transferring elements of the image from the internal surface of the envelope wall to the external surface to facilitate recording of an image on a sensitised sheet presented to the external surface. Deflection means guide a recording beam either to the monitoring screen or to the second output portion of the envelope, as required, or alternately to the two output portions of the envelope in rapid succession.

United States Patent [191 Allen [451 Jan. 29, 1974 CATHODE RAY TUBES TOFACILITATE RECORDING [75] Inventor: Gordon S. J. Allen, Essex, England[73] Assignee: Forward Technology Limited,

London, England [22] Filed: May 8, 1972 [21] Appl. No.: 251,299

[52] US. Cl 315/21 PR, 178/66 A, 346/110 R [51] Int. Cl. H01j 29/70 [58]Field of Search. 315/21 R, 21 PR; l78/D1G. 2,

[56] References Cited UNITED STATES PATENTS 3,220,012 11/1965 Schwertz178/66 A 3,283,069 11/1966 McGriff 315/21 R 3,040,124 6/1962 Camras315/21 PR 3,585,432 6/1971 Oberg 178/D1G; 2

Attomey, Agent, or Firm-Kemon, Palmer &

I Estabrook [57] ABSTRACT A cathode ray tube with a conventional screenfor providing a visible monitoring image is additionally formed with asecond output portion on its envelope, the second output portionincluding a multiplicity of fibre-optics, electrically conductiveparticles, or other elements for transferring elements of the image fromthe internal surface of the envelope wall to the external surface tofacilitate recording of an image on a sensitised sheet presented to theexternal surface. Detlection means guide a recording beam either to themonitoring screen or to the second output portion of the envelope, asrequired, or alternately to the two output portions of the envelope inrapid succession.

11 Claims, 5 Drawing Figures 35 Pas/2700 CATHODE RAY TUBES TO FACILITATERECORDING Cathode ray tubes may have already been used to providevisible alpha-numerical information, for example as a monitor at theoutput of a computer or for photocomposing. The characters may begenerated on the face of a cathode ray tube by means of circuits whichsynthesise the character shapes or by using templates within a tube tocreate the required characters, for example. Usually, it is alsorequired to have a permanent record of at least some of the output of acomputer and consequently the data signals are separately fed to a highspeed printer.

According to the present invention, a single cathode ray tube has, inaddition to a gun for generating an electron beam with means formodulating the beam, deflection means for deflecting the beam at anyinstant to either of two paths so that the modulated beam forms similarimages in two alternative positions on the tube envelope, the imageformed in at least one of the positions being visible and providing amonitoring output and the tube wall at the position of the other imageincluding a multiplicity of elements for transferring elements of theimage, or representations of the said image elements, from the internalsurface of the tube wall to the external surfacethereof to facilitaterecording of the image on a sensitised sheet. The reference to similarimages in two alternative positions means that the same instantaneousimage modulation is produced at the two alternative positions. It doesnot means that the two images are necessarily both visible or both ofthe same form; for example, the image at the position at which recordingwill take place may consist of a single scanning line, movement of asensitised sheet taking the place of the frame scan present in themonitoring image.

As an example, the image for recording may be formed on a side wall ofthe tube. To facilitate recording, the part of the tube on which thisother image is formed may consist of a piece of fibre-optic materialproviding a highly efficient light coupling to the outside of the tube.Images may then be reproduced on a lightsensitive sheet by directcontact of the sheet with the outside of the fibre-optic material. Thelight-sensitive sheet may, for example, pass over a roller in contactwith the external ends of the fibre-optics. Only a narrow fibre-opticsstrip is necessary, since the lightsensitive sheet may be in continuousmovement.

In an alternative form, the multiplicity of elements consists ofelectrically conductive particles in the tube wall capable oftransferring representations of the image elements, in the form ofelectric charges, from the beam of the tube to the external wall of theenvelope so that characters may be electrically recorded on a sensitisedsheet at the external wall.

In order that the invention may be better understood, one example willnow be described with reference to the accompanying drawings, in which:

FIG. la shows diagrammatically a cathode ray tube with two alternativebeam paths;

FIG. 1b shows the fibre-optics strip in the bottom of the cathode raytube shown in FIG. la;

FIG. 2 illustrates the path of the recording sheet with a tube of thekind shown in FIG. la;

FIG. 3 shows a tube face with the fibre-optics strip in an alternativeposition; and

FIG. 4 illustrates an alternative form of recording strip for thecathode ray tube.

In FIG. 1, the beam 10 within the cathode ray tube 12 can follow eitherof the paths 10a or 10b, depending upon the potentials applied to thedeflector plates 14. When the beam follows the path 10a it produces anormal monitoring visible output on the screen 16 of the cathode raytube. When it follows the path 10b it scans over a very narrow strip 18of fibre-optic elements in the bottom face of the tube (see also FIG.1b). For the path 10b, the frame deflection may be just sufficient toaccommodate a line of type and the image reproduced by the fibre-opticsmay be stationary during recording or may move continuously in the framedirection of the fibre-optic strip. Alternatively, the phosphor behindthe fibre-optic strip may be subjected to repetitive scanning along asingle scanning line. The fibre-optic material efficiently couples thelight generated at the phosphor to the outside of the tube. As shown inFIG. 2, a recording paper 20 is drawn by a driven roller 23 over aroller 22, the axis of which lies immediately under the fibre-opticstrip, the paper being substantially in contact with the outer surfaceof the fibre-optic strip. The paper is advanced continuously if there isa single line scan along the phosphor behind the fibreoptic strip.

FIG. 2 also shows the electron gun 27 with cathode 28 and the horizontaland vertical deflection plates 29 and 14, the horizontal deflectionplates being connected to a line scan deflection generator 31 and thevertical deflection plates being connected to a semiamplifier32 whichadds signals received from a position selector 33 and the normal framescan deflection generator 34. Switches 35 and 36, shown as contactswitches for convenience, are connected in the two input leads to theamplifier 32 and are coupled for simultaneous operation. The switch 35permits the position selector 33 to add its deflecting bias whenrequired and the switch 36 permits one of two outputs of the frame scangenerator 34 to be selected, a first of these outputs giving a fullheight monitoring picture on the front face of the tube envelope and thesecond of the two outputs giving a very restricted vertical scan, foruse when the switches cause the beam to be deflected on to thefibre-optic strip 18.

FIG. 3 shows a form of cathode ray tube in which a single linefibre-optic strip 18a is set into the bottom part of the front face 16of the cathode ray tube 12, under the area 24 occupied by the monitoringscan.

FIG. 4 shows an alternative form of cathode ray tube in which the bottomwall includes a piece of material including fine electrically conductivesubstances 26 to transfer an electric charge from the cathode ray tubebeam to the external surface of the tube envelope so that characters maybe electrically recorded on a sensitised sheet at the external wall ofthe envelope.

In its recording position, the light beam may also be used to dischargea photoconductive transfer plate for xerographic recording.

The field which forms the image in the second position may beelectromagnetic or electrostatic. It may be a simple deflection fieldthat simply changes the angle of the beam whilst maintaining its focusand other characteristics or it may completely reform the image in thesecond position.

Where occasional printing of the visible monitoring output is required,a switch can be arranged to permit an operator watching the tube screento cause the beam to be deflected to the printing image position when hewishes the visible output to be recorded. The tube thus acts as monitorand printer on a time-sharing basis. If printing and the monitoringoutput are required together, for example if all the data appearing inthe monitoring position is to be recorded, the timesharing operation canbe made to occur at a much higher frequency.

Although the primary use of the invention is expected to be in the fieldof alpha-numeric data presentation and recording, it wlll be appreciatedthat it can also be used with other kinds of image, for example curvesor drawings.

I claim: l. A cathode ray tube comprising: an envelope having first andsecond output portions; a gun for generating an electron beam includingmeans for modulating the beam; deflection means for deflecting the beamat any instant to either of two paths so that the modulated beam definescorresponding image elements at said first and second output portions ofsaid envelope;

said first output portion of said envelope carrying a luminescent screento provide a visible monitoring image;

and said second output portion of said envelope including a multiplicityof elements for transferring elements of the image from the internalsurface of said second output portion of said envelope to the externalsurface thereof to facilitate recording of the image on a sensitisedsheet presented to said external surface.

2. A cathode ray tube in accordance with claim 1, in which saidmultiplicity of elements at said second output portion consists of fibreoptics having a phosphor material coated on their inner surfaces.

3. A cathode ray tube in accordance with claim 2, in which the fibreoptics together form a narrow strip in the tube envelope.

4. A cathode ray tube in accordance with claim 1, in which saidmultiplicity of elements at saidsecond output portion consists ofelectrically conductive particles in the tube envelope capable oftransferring an electric charge from said beam to said external surfaceof said second output portion so that characters may be electricallyrecorded on a sensitised sheet at said external surface.

5. A cathode ray tube in accordance with claim 1, in which the part of.the envelope on which said second output portion is formed is in a sidewall of the envelope.

6. A cathode ray tube in accordance with claim 1, in

which both the first and second output portions of the envelope areformed are in the front wall. of the envelope.

7. Cathode ray tube apparatur comprising:

a cathode ray tube including an envelope having first and second outputportions, and also including a gun for generating an electron beamincluding means for modulating the beam, and beamdeflecting members;

deflection-control means connected to said beamdeflecting members fordeflecting the electron beam at any instant to either of said first andsecond output portions to define similar image ele-' ments at said firstand second portions;

said first output portion of said envelope carrying a luminescent screento provide a visible monitoring image;

and said second output portion of said envelope including a multiplicityof elements for transferring elements of the image from the internalsurface of said second output portion of said envelope to the externalsurface thereof to facilitate recording of the image on a sensitisedsheet; and

means for presenting a sensitised sheet to said external surface of saidsecond output portion of said envelope.

8. Apparatus in accordance with claim 7, in which saiddeflection-control means deflects said electron beam over only a narrowstrip at said second output portion of said envelope.

9. Apparatus in accordance with claim 8, in which said second outputportion of said envelope consists of a narrow strip including amultiplicity of fibre optics elements, the apparatus further including aroller positioned adjacent the external surface of said second outputportion of the envelope and means for passing a record material over theroller substantially in contact with said fibre-optics strip.

10. Cathode ray tube apparatus including a cathode ray tube inaccordance with claim 1, further including a manually operable switch topermit the beam to be deflected to form an image on said second outputportion of the envelope when required by an operator watching themonitoring first output portion of the envelope.

l1. Cathode ray tube apparatus including a cathode ray tube inaccordance with claim 1, including switching means for deflecting thebeam between said first and second output portions of said envelopealternately at high speed so that the image elements at said two outputportions are formed substantially simultaneously.

1. A cathode ray tube comprising: an envelope having first and secondoutput portions; a gun for generating an electron beam including meansfor modulating the beam; deflection means for deflecting the beam at anyinstant to either of two paths so that the modulated beam definescorresponding image elements at said first and second output portions ofsaid envelope; said first output portion of said envelope carrying aluminescent screen to provide a visible monitoring image; and saidsecond output portion of said envelope including a multiplicity ofelements for transferring elements of the image from the internalsurface of said second output portion of said envelope to the externalsurface thereof to facilitate recording of the image on a sensitisedsheet presented to said external surface.
 2. A cathode ray tube inaccordance with claim 1, in which said multiplicity of elements at saidsecond output portion consists of fibre optics having a phosphormaterial coated on their inner surfaces.
 3. A cathode ray tube inaccordance with claim 2, in which the fibre optics together form anarrow strip in the tube envelope.
 4. A cathode ray tube in accordancewith claim 1, in which said multiplicity of elements at said secondoutput portion consists of electrically conductive particles in the tubeenvelope capable of transferring an electric charge from said beam tosaid external surface of said second output portion so that charactersmay be electrically recorded on a sensitised sheet at said externalsurface.
 5. A cathode ray tube in accordance with claim 1, in which thepart of the envelope on which said second output portion is formed is ina side wall of the envelope.
 6. A cathode ray tube in accordance withclaim 1, in which both the first and second output portions of theenvelope are formed are in the front wall of the envelope.
 7. Cathoderay tube apparatur comprising: a cathode ray tube including an envelopehaving first and second output portions, and also including a gun forgenerating an electron beam including means for modulating the beam, andbeam-deflecting members; deflection-control means connected to saidbeam-deflecting members for deflecting the electron beam at any instantto either of said first and second output portions to define similarimage elements at said first and second portions; said first outputportion of said envelope carrying a luminescent screen to provide avisible monitoring image; and said second output portion of saidenvelope including a multiplicity of elements for transferring elementsof the image from the internal surface of said second output portion ofsaid envelope to the external surface thereof to facilitate recording ofthe image on a sensitised sheet; and means for presenting a sensitisedsheet to said external surface of said second output portion of saidenvelope.
 8. Apparatus in accordance with claim 7, in which saiddeflection-control means deflects said electron beam over only a narrowstrip at said second output portion of said envelope.
 9. Apparatus inaccordance with claim 8, in which said seconD output portion of saidenvelope consists of a narrow strip including a multiplicity of fibreoptics elements, the apparatus further including a roller positionedadjacent the external surface of said second output portion of theenvelope and means for passing a record material over the rollersubstantially in contact with said fibre-optics strip.
 10. Cathode raytube apparatus including a cathode ray tube in accordance with claim 1,further including a manually operable switch to permit the beam to bedeflected to form an image on said second output portion of the envelopewhen required by an operator watching the monitoring first outputportion of the envelope.
 11. Cathode ray tube apparatus including acathode ray tube in accordance with claim 1, including switching meansfor deflecting the beam between said first and second output portions ofsaid envelope alternately at high speed so that the image elements atsaid two output portions are formed substantially simultaneously.